Along with high integration of semiconductor devices to be incorporated in, precise fineness of packages, high-density wiring of a printed wiring board, and improvement of the joining and mounting technology, the recent electronic appliances is advanced remarkably and especially development of the electronic appliances such as the mobile communication utilizing high frequency is outstanding.
A printed wiring board composing such kinds of electronic appliances tends to be multilayered and simultaneously to have ultra fine wiring, and therefore, it is efficient to lower the dielectric constant of a material to meet the speed up of the signal transmission speed required for the high speed of the information processing and also it is effective to use a material with a low dielectric dissipation factor (dielectric loss) in order to lower the loss of transmission.
Relying on the excellency in the high frequency properties of such as the dielectric constant, the dielectric loss and the like, poly(phenylene oxide) resin [also referred as to polyphenylene ether (PPE)] is suitable for the printed wiring boards of such electronic appliances using the high frequency bands, however, generally it cannot be said that the poly(phenylene oxide) resin has been sufficient in the heat resistance and dimensional stability.
The applicant of the present invention discloses a poly(phenylene oxide) resin composition provided with improved heat resistance and dimensional stability, a production method of prepreg using the poly(phenylene oxide) resin composition, and a production method of a laminated sheet using the prepreg in Japanese Unexamined Patent Publication No. 7-90172 and also discloses a poly(phenylene oxide) resin composition having a high glass transition temperature, water resistance, moisture resistance, and moisture-absorbing heat resistance in addition to the improvement of the heat resistance and dimensional stability, a production method of prepreg using the poly(phenylene oxide) resin composition, and a production method of a laminated sheet using the prepreg in Japanese Unexamined Patent Publication No. 8-231847.
However, poly(phenylene oxide) itself has a high melting point, the prepreg produced using the poly(phenylene oxide) resin composition has a high melt viscosity and subsequently, for example, when prepreg are layered on a printed wiring board in which conductive patterns are formed as a circuit on the surface and molded by hot pressing in order to produce a multilayer printed wiring board, the viscosity is high and the fluidity is low at the time of melting at a normal molding temperature to make it difficult to sufficiently fill the spaces between neighboring conductive patterns with the resin and easy to leave voids and blurs, and thus there are problems in molding properties.
The invention has been achieved by taking the above described points into consideration and the object is to provide a poly(phenylene oxide) resin composition excellent in the fluidity in the melted state at the time of molding and in molding properties and also to provide prepreg using the poly(phenylene oxide) resin composition, a laminated sheet, a printed wiring board, and a multilayer printed wiring board.